Injection device

ABSTRACT

An injection device includes a housing, a dosing member held so as to be rotatable and fixed in the housing and an injection sleeve held so as to be rotationally fixed in relation to the housing and displaceable therein. A latching unit of the injection device is configured to act between two components thereof which, during setting of an amount of injection fluid to be dispensed, move relative to one another. A set amount of injection fluid is unequivocally assigned to each relative position of the two components.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 15/230,320, filed Aug. 5, 2016, which, in turn, is acontinuation application of international patent applicationPCT/EP2015/000205, filed Feb. 3, 2015, designating the United States andclaiming priority from German application 20 2014 001 134.6, filed Feb.5, 2014, and the entire content of the above applications isincorporated herein by reference.

BACKGROUND OF THE INVENTION

An injection device in which a latching part which is connected in arotationally fixed manner to the operating button and interacts with theinjection sleeve is provided is known from WO 2013/117332 A1. Whensetting an amount of injection fluid to be squeezed out, the operatingbutton is rotated in relation to the housing, and when the injectionfluid is being squeezed out, is held so as to be rotationally fixed inrelation to the housing and guided in the longitudinal direction of theinjection device. When setting an amount of injection fluid to besqueezed out, and when the injection fluid is being squeezed out of thecontainer, the injection sleeve is moved in the direction of thelongitudinal central axis of the injection device, without being rotatedin relation to the housing. On account thereof, the rotational positionof the operating button in relation to the injection sleeve is modifiedin the case of each injection procedure.

A second latching installation of WO 2013/117332 A1 acts between ahousing part and a dosing member. The dosing member rotates when settingthe amount of an injection fluid to be squeezed out, and the dosingmember rotates back when the amount of injection fluid to be squeezedout is being squeezed out. The latching installation has two latchingarms which are disposed so as to be mutually opposite. Since the dosingmember is rotatable about the longitudinal central axis by multiplerotations, each latching position is reached multiple times when settingthe maximum dosage.

If and when, for example, amounts of 0.20 ml and 0.25 ml of injectionfluid which are to be set for a therapy are required, then knowninjection devices are conceived such that dosing increments of at most0.05 ml are settable. This means, on the one hand, that the user has toovercome a plurality of latching steps until the minimum dosage which isprovided for the therapy is reached. On the other hand, the amount ofinjection fluid which has to be discarded during the priming procedureis comparatively sizeable in the case of a minimum fixed dosageincrement of 0.05 ml, for example. Therefore, significantly smallerdosing increments would be desirable for the priming procedure. However,this leads to a significantly increased number of latching positionswhich have to be overcome by the user when setting the dosage.

SUMMARY OF THE INVENTION

It is an object of the invention to provide an injection device whichenables a plurality of latching positions to be disposed at variablespacings.

An injection device defines a longitudinal center axis, a proximaldirection and a distal direction. The injection device includes: ahousing; a dosing member held so as to be rotatable and fixed in thehousing in the direction of the longitudinal center axis; an injectionsleeve held so as to be rotationally fixed in relation to the housingand displaceable in the direction of the longitudinal center axis; thedosing member being connected to the injection sleeve via a firstthreaded connection; the dosing member being configured to rotate in afirst rotational direction in relation to the housing when an amount ofinjection fluid to be dispensed is being set; the injection sleeve beingconfigured to move in the distal direction because of the first threadedconnection; the dosing member being further configured to rotate in asecond rotational direction counter to the first rotational directionwhen the amount of injection fluid to be dispensed is being pressed out;the injection sleeve being configured to move in the proximal directionbecause of the first threaded connection; a container configured tocontain injection fluid; a dosing piston configured to press injectionfluid out of the container; the dosing piston being connected to thedosing member via a second threaded connection; the dosing piston beingconnected to the dosing member in a rotationally fixed manner so as torotate conjointly therewith when the amount of injection fluid to bedispensed is being set; the dosing piston being connected to theinjection sleeve in a rotationally fixed manner when the amount ofinjection fluid to be dispensed is pressed out and, by virtue of thesecond threaded connection, is moved in the proximal direction; alatching unit configured to act at least when the amount of injectionfluid to be dispensed is being set; and, the latching unit beingconfigured to act between two components of the injection device whichduring setting of the amount of injection fluid to be dispensed, moverelative to one another, wherein a set amount of injection fluid isunequivocally assigned to each relative mutual position of the twocomponents.

The present invention provides that the latching installation actsbetween two components of the injection device wherein each relativemutual position of the two components is unequivocally assigned a setamount of injection fluid. On account thereof, the required latchingpositions may be disposed at variable mutual spacings. For example, aninjection device which provides precisely three latching positions at0.01 ml for the priming procedure, and at 0.20 ml and 0.25 ml for thedosages to be injected, could be provided for the exemplary therapywhich has been described at the outset. Operating the injection deviceis significantly simplified on account thereof. Where reference is madehereunder to “the two components”, this means the two components betweenwhich the latching installation is in effect and in which case eachrelative mutual position is unequivocally assigned a set amount ofinjection fluid.

The latching installation advantageously has at least one latchingelement and at least one counter-latching element which in a latchingposition interacts with the latching element.

Advantageously, one of the two components between which the latchinginstallation acts is the dosing member, and the other of the twocomponents is the injection sleeve. When setting the amount of injectionfluid to be squeezed out, the dosing member and the injection sleeve aremoved in relation to one another in helical manner, since the dosingmember performs a rotation movement, and the injection sleeve performs amovement in the direction of the longitudinal central axis of theinjection device. When the injection fluid is being squeezed out, thedosing member and the injection sleeve move back from one another totheir respective initial position. On account thereof, precisely one setamount of injection fluid is assigned to each relative mutual positionof the dosing member and the injection sleeve.

It may also be provided that one of the two components between which thelatching installation acts is the injection sleeve, and the other of thetwo components is the housing. The injection sleeve moves in thedirection of the longitudinal central axis of the injection device whensetting an amount of injection fluid to be squeezed out. When theinjection fluid is being squeezed out, the injection sleeve moves backto the initial position thereof. On account thereof, each axial positionof the injection sleeve corresponds to precisely one set amount ofinjection fluid.

The statement that the latching installation acts between the twocomponents means that the latching installation is effective betweenthese components, but does not mean that the latching element and thecounter-latching element have to be disposed on the two components perse. Rather, the latching element and the counter-latching element may beconfigured on further components which likewise perform the relativemutual movement of the two components and, on account thereof, areeffective between the two components.

It is provided that the injection device has an operating element. Theoperating element advantageously has a distal position in which theoperating element is located when setting the amount of injection fluidto be squeezed out, and a proximal position in which the operatingelement is located when the amount of injection liquid to be squeezedout is being squeezed out. The distal position and the proximal positionof the operating element here are positions of the operating element inrelation to the injection sleeve. Advantageously, the operating elementby way of a first coupling is connectable in a rotationally fixed mannerto a follower or entrainer which is connected in a rotationally fixedmanner to the dosing member, and by way of a second coupling isconnectable to the injection sleeve. In the distal position of theoperating element, the operating element by way of the first coupling isadvantageously connected in a rotationally fixed manner to theentrainer. The second coupling in the distal position of the operatingelement is advantageously opened such that the operating element isrotatable in relation to the injection sleeve. In the proximal positionof the operating element the first coupling is advantageously opened,and the operating element is rotatable in relation to the entrainer, andthe operating element by way of the second coupling is connected in arotationally fixed manner to the injection sleeve. The operating elementis rotated when setting an amount of injection fluid to be set. Theentrainer, the dosing member, and the dosing piston which is connectedin a rotationally fixed manner to the operating element rotateconjointly with the operating element. When injection fluid is beingsqueezed out the operating element is connected in a rotationally fixedmanner to the injection sleeve and, on account thereof, is guided in arotationally fixed manner in relation to the housing. The entrainerconjointly with the dosing member rotates about the longitudinal centralaxis of the injection device, and by way of the second threadedconnection moves the dosing piston in the proximal direction. On accountthereof, the injection fluid is squeezed out of the container.

Comfortable operation results when the latching installation iseffective only when setting the amount of injection fluid to be squeezedout, but not during the injection procedure. This may be achieved in asimple manner in that the latching installation is coupled to theposition of the operating element, and is effective in the distalposition of the operating element. In the proximal position of theoperating element, the at least one latching element and the at leastone counter-latching element advantageously are mutually disengaged,independently of the relative mutual position of the two components. Ifand when the latching installation is effective only when setting anamount of injection fluid to be squeezed out, the latching elementand/or the counter-latching element may be configured so as to beasymmetrical such that a significantly higher force is required forovercoming a latching position in order to reduce the set amount ofinjection fluid to be squeezed out than for setting an amount ofinjection fluid to be squeezed out.

Advantageously, one of the two components between which the latchinginstallation acts is the entrainer, and the other of the two componentsis the injection sleeve. A simple construction of the injection deviceresults on account thereof. In the case of injection devices in whichthe operating element is rotated by fewer than one revolution in orderfor the maximum dosage to be reached, precisely one set amount ofinjection fluid is assigned to each relative rotational position of theentrainer and the injection sleeve. Advantageously, the entrainer in thedirection of the longitudinal central axis is coupled to the position ofthe injection sleeve such that the entrainer moves conjointly with theinjection sleeve in the distal direction when setting the amount ofinjection fluid to be squeezed out, and moves in the proximal directionwhen the set amount of injection fluid is being squeezed out. On accountthereof, a simple construction of the first coupling which acts betweenthe entrainer and the operating element is enabled.

A simple construction of the injection device results if and when atleast one latching element is disposed on the one of the two components,and at least one counter-latching element is disposed on the other ofthe two components. In a particularly advantageous manner, the latchingelement and the counter-latching element, respectively, are configuredso as to be integral with the respective component. A fixed connectionto the respective component may also be advantageous in particular inorder for the production of the component to be simplified.

In order for it to be achieved in a simple manner that the latchinginstallation is effective only when setting an amount of injection fluidto be set, but not when the injection fluid is being squeezed out, it isadvantageous for at least one latching element to be disposed on onelatching part which is connected in a rotationally fixed manner to oneof the two components, so as to be displaceable in relation to thiscomponent in the direction of the longitudinal central axis.Advantageously, at least one counter-latching element is disposed on theother of the two components. The at least one latching element in afirst axial position of the latching part may advantageously come intoengagement with the at least one counter-latching element. The at leastone latching element, in a second axial position of the latching part,independently of the relative mutual position of the two components, isadvantageously disengaged from the at least one counter-latchingelement.

A simple construction results when the position of the latching part islinked to the position of the operating element such that the latchingpart, in the distal position of the operating element, is located in thefirst axial position thereof and, in the proximal position of theoperating element, is located in the second axial position thereof. Thelatching part is advantageously elastically biased in the directiontoward the first axial position thereof, preferably by at least onespring.

A simple construction having a minor number of individual parts resultswhen the latching part has at least one spring arm which biases thelatching part in the direction toward the first axial position thereof.The spring arm advantageously is configured so as to be integral withthe latching part such that no additional spring is required for biasingthe latching part in the direction toward the first axial positionthereof.

Advantageously, a spring which biases the dosing member in the secondrotation direction acts between the injection sleeve and the dosingmember. On account thereof, the dosing member is reset in the directiontoward the next latching position which corresponds to the next lowestamount of injection fluid to be set, when the operating element isreleased between two latching positions. On account thereof, inadvertentsqueezing out of an unintended amount of injection fluid is prevented ina simple manner. Since the injection sleeve in relation to the dosingmember moves in the direction of the longitudinal central axis whensetting an amount of injection fluid to be squeezed out, the springadvantageously is connected to the entrainer which is connected in arotationally fixed manner to the dosing member. Advantageously, thespring by way of one end is secured to the injection sleeve, and by wayof the other end is secured to the entrainer. A simple construction ofan injection device which has a latching part results when the spring byway of one end is secured to the latching part, and by way of the otherend is secured on the entrainer. A spring which biases the dosing memberin the second rotation direction is advantageous in particular in thecase of an injection device in which the latching installation thereofis only effective when setting an amount of injection fluid, but notwhen the latter is being squeezed out. The latching installationadvantageously is configured such that to overcome the latchingpositions a lesser force is required for setting an amount of injectionfluid to be squeezed out, than for turning back in the oppositedirection. On account thereof, when the operating element is releasedbetween two latching positions, it may be ensured that the dosing memberis reset only to the next lowest latching position and that this latterlatching position cannot be overcome. At the same time, the spring whichbiases the dosing member in the second rotation direction may beconceived to be so strong that reliable turning back of the dosingmember is also ensured in the case of unfavorable friction conditionsand tolerances.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described with reference to the drawingswherein:

FIG. 1 shows a side view of a first embodiment of an injection device inthe zero position;

FIG. 2 shows a section along the line II-II in FIG. 1;

FIG. 3 shows a side view of the injection device of FIG. 1, aftersetting an amount of injection fluid to be squeezed out;

FIG. 4 shows a section along the line IV-IV in FIG. 3;

FIG. 5 shows a side view of the injection device of FIG. 1, aftersetting an amount of injection fluid to be squeezed out and displacingthe operating element in the proximal direction;

FIG. 6 shows a section along the line VI-VI in FIG. 5;

FIG. 7 shows a side view of the entrainer, the spring, and the latchingpart of the injection device of FIGS. 1 to 6;

FIG. 8 shows a side view of the assembly in FIG. 7, in the direction ofthe arrow VIII in FIG. 7;

FIG. 9 shows a plan view in the direction of the arrow IX in FIG. 7;

FIG. 10 shows the fragment X of FIG. 9, in an enlarged illustration;

FIGS. 11 and 12 show perspective illustrations of the entrainer of theinjection device of FIGS. 1 to 6;

FIG. 13 shows a side view of the entrainer;

FIG. 14 shows a side view in the direction of the arrow XIV in FIG. 13;

FIG. 15 shows a section along the line XV-XV in FIG. 14;

FIGS. 16 and 17 show perspective illustrations of the latching part ofthe injection device of FIGS. 1 to 6;

FIG. 18 shows a side view of the latching part of FIGS. 16 and 17;

FIG. 19 shows a section along the line XIX-XIX in FIG. 18;

FIGS. 20 and 21 show perspective illustrations of the operating elementof the injection device;

FIG. 22 shows a side view of the operating element;

FIG. 23 shows a section along the line XXIII-XXIII in FIG. 22;

FIG. 24 shows a view of the operating element, in the direction of thearrow XXIV in FIG. 22;

FIGS. 25 to 27 show perspective illustrations of the injection sleeve ofthe injection device;

FIGS. 28 and 29 show side views of the injection sleeve;

FIG. 30 shows a section along the line XXX-XXX in FIG. 29;

FIG. 31 shows the fragment XXXI of FIG. 30, in an enlarged illustration;

FIG. 32 shows a section along the line XXXII-XXXII in FIG. 30;

FIGS. 33 and 34 show side views of the dosing member;

FIG. 35 shows a section along the line XXXV-XXXV in FIG. 33;

FIG. 36 shows a section along the line XXXVI-XXXVI in FIG. 33;

FIG. 37 shows a perspective illustration of a piston rod of theinjection device of FIGS. 1 to 6;

FIG. 38 shows a side view of the piston rod of FIG. 37;

FIG. 39 shows a section along the line XXXIX-XXXIX in FIG. 38;

FIGS. 40 and 41 show side views of a housing part of the injectiondevice of FIGS. 1 to 6;

FIG. 42 shows a section along the line XLII-XLII in FIG. 41;

FIG. 43 shows a section along the line XLIII-XLIII in FIG. 41;

FIG. 44 shows a side view of a holder of the injection device of FIGS. 1to 6;

FIG. 45 shows a section along the line XLV-XLV in FIG. 44;

FIG. 46 shows an injection sleeve, a latching part, and an entrainer ofan embodiment of an injection device;

FIG. 47 shows a section along the line XLVII-XLVII in FIG. 46;

FIGS. 48 to 52 show perspective illustrations of the latching part ofFIGS. 46 and 47;

FIG. 53 shows a side view of an embodiment of an injection sleeve of aninjection device;

FIG. 54 shows a section along the line LIV-LIV in FIG. 53;

FIG. 55 shows a section along the line LV-LV in FIG. 54;

FIG. 56 shows a side view of an embodiment of an entrainer of aninjection device;

FIG. 57 shows a section along the line LVII-LVII in FIG. 56;

FIG. 58 shows the fragment LVIII in FIG. 57, in an enlargedillustration;

FIGS. 59 and 60 show side views of an embodiment of an injection deviceafter setting an amount of injection fluid to be squeezed out;

FIG. 61 shows a section along the line LXI-LXI in FIG. 60;

FIG. 62 shows the fragment LXII in FIG. 61, in an enlarged illustration;

FIG. 63 shows a perspective illustration of an embodiment of a dosingmember;

FIG. 64 shows the fragment LXIV of FIG. 63, in an enlarged illustration;

FIG. 65 shows a side view of the dosing member of FIG. 63;

FIG. 66 shows a section along the line LXVI-LXVI in FIG. 65;

FIG. 67 shows a side view of an embodiment of an injection sleeve;

FIG. 68 shows a section along the line LXVIII-LXVIII in FIG. 67;

FIG. 69 shows a section along the line LXIX-LXIX in FIG. 67;

FIG. 70 shows a side view of an injection device in the zero position;

FIG. 71 shows a section along the line LXXI-LXXI in FIG. 70;

FIG. 72 shows a side view of the injection device of FIG. 70 aftersetting an amount of injection fluid to be squeezed out;

FIG. 73 shows a section along the line LXXIII-LXXIII in FIG. 72.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

FIG. 1 shows an injection device 1 which has a housing 2. The housing 2includes an upper distal housing part 3, and a holder 4 which isdisposed on the proximal side of the upper housing part 3. An injectionneedle 8 is secured to the proximal side of the holder 4. Adjacent tothe injection needle 8, the holder 4 has a latching installation 9, acontainer 5 shown in FIG. 2 being latched thereto in the holder 4. Anoperating element 6 is disposed on the distal side of the injectiondevice 1. As is shown in FIG. 1, the injection device 1 has alongitudinal central axis 50 which runs in the longitudinal direction ofthe injection device 1. The upper housing part 3 has a viewing window 7which is configured so as to be at least partially transparent. Theviewing window 7 in FIG. 1 is drawn in a schematic and non-transparentmanner such that the components lying therebelow are not visible in FIG.1.

The distal end of the injection device 1 is that end that faces awayfrom an injection needle 8 which is held on the injection device.“Proximal” refers to that side of the injection device 1 that faces thepuncture when injecting, “distal” referring to that side that faces awayfrom the puncture. The proximal direction refers to the direction ofinjection, that is, the direction toward the injection needle 8, or thatdirection in which the injection fluid is squeezed out of the container5, respectively. The distal direction refers to the opposite direction,that is, away from the injection needle 8.

As is shown in FIG. 2, a plug 10, a piston disk 13 of a dosing piston 11bearing thereon, is disposed in the container 5. The dosing piston 11moreover includes a piston rod 12 which carries an external thread 92.

An injection sleeve 17, the external side thereof being visible throughthe viewing window 7 of the upper housing part 3, is disposed in theupper housing part 3. The injection sleeve 17 has an opening 26, theexternal circumference of a dosing member 18 which is disposed withinthe injection sleeve 17 being visible therethrough. The dosing member18, which may also be referred to as a graduated tube, on the externalcircumference thereof carries a graduation (not visible in FIG. 2) whichto the operator is visible through the viewing window 7 and the opening26.

The injection sleeve 17 in the upper housing part 3 is held so as to bedisplaceable in the direction of the longitudinal central axis 50 and soas to be rotationally fixed in relation to the upper housing part 3. Thedosing member 18 and the injection sleeve 17 are interconnected by wayof a first threaded connection 19. An entrainer 14 which is connected ina rotationally fixed manner to the dosing member 18 is disposed withinthe dosing member 18. The entrainer 14 has a circumferential groove 63,a retaining periphery 64 of the injection sleeve 17 protrudingthereinto. The retaining periphery 64 here is held with a clearance inthe circumferential groove 63. On account thereof, the injection sleeve17 and the entrainer 14 are interlinked in the direction of thelongitudinal central axis 50. However, by virtue of the clearance, minorrelative movement between the injection sleeve 17 and the entrainer 14in the direction of the longitudinal central axis 50 is possible.

The dosing member 18 by way of a latching connection 71 is held in theupper housing part 3 so as to be fixed in the direction of thelongitudinal central axis 50. In the embodiment the latching connection71 is disposed at the proximal end of the dosing member 18. The dosingmember 18 by way of a pivot bearing 21 is rotatably mounted in the upperhousing part 3. The dosing member 18 by way of a second threadedconnection 22 is connected to the piston rod 12 of the dosing piston 11.The operating element 6 by way of an entrainment portion 51 is connectedin a rotationally fixed manner to the piston rod 12.

The operating element 6 in FIG. 2 is shown in the distal position 90thereof in relation to the injection sleeve 17. The operating element 6by way of a first coupling 16 is connectable to the entrainer 14. In thedistal position 90 of the operating element 6, the operating element 6and the entrainer 14 are interconnected in a rotationally fixed mannerby way of the first coupling 16. A latching part 15 is disposed in theoperating element 6. The latching part 15 in the embodiment isconfigured so as to be annular, being disposed on the externalcircumference of the entrainer 14. A latching installation 35 which willbe described in yet more detail hereunder is formed between theentrainer 14 and the latching part 15. The latching part 15 is connectedin a rotationally fixed manner to the injection sleeve 17. The latchingpart 15 is movable in the direction of the longitudinal central axis 50,being biased by a spring 23 in the direction toward the first axialposition 88 of the latching part 15, as shown in FIG. 2.

A second coupling 20 which is opened in the zero position 28 of theinjection device 1, as shown in FIG. 2, is provided between theoperating element 6 and the injection sleeve 17. On account thereof, theoperating element 6 is rotatable in relation to the injection sleeve 17.No dosage is set in the zero position 28. In the zero position 28 theinjection sleeve 17 bears on a first stop 24 on the upper housing part3.

In order for an amount of injection fluid to be squeezed out to be set,the operator rotates the operating element 6 in a first rotationdirection, being the clockwise direction in the embodiment. Theentrainer 14 and the dosing member 18 which is connected in arotationally fixed manner to the entrainer 14 are conjointly rotated byway of the first coupling 16. The piston rod 12 is also conjointlyrotated by way of the entrainment portion 51 of the operating element 6.The injection sleeve 17, by virtue of the first threaded connection 19and of the rotationally fixed fixation of the injection sleeve 17 in theupper housing part 3, is moved in the distal direction 30. The entrainer14 and the operating element 6 also move conjointly with the injectionsleeve 17. Since the entrainer 14 moves in relation to the latching part15 which is connected in a rotationally fixed manner to the injectionsleeve 17, the latching increments of the latching installation 35 areperceivable and audible to the operator. The latching installation 35 iseffective when setting an amount of injection fluid to be squeezed out.

FIGS. 3 and 4 show the injection device 1 in the injection position 29,after setting an amount of injection fluid to be squeezed out. Theoperating element 6 here has been rotated by fewer than one fullrevolution in relation to the upper housing part 3. The injection sleeve17 in the distal direction has partially moved out of the upper housingpart 3. As is shown in FIG. 4, the spring 23 is not only configured as acompression spring, but additionally acts as a torsion spring. To thisend, the spring 23 by way of a first end 84 is hooked to the latchingpart 15, and by way of a second end 85 is hooked to the entrainer 14.The spring 23 is tensioned when the operating element 6 is rotated inthe first rotation direction. If and when the operating element 6between two latching positions of the latching installation 35 isreleased by the operator, the spring 23 turns the entrainer 14 and,conjointly with the entrainer, the dosing member 18 back to the nextlowest latching position, that is, to that latching position whichcorresponds to the next lowest envisaged amount of injection fluid.Moreover, the spring 23 biases the latching part 15 to the first axialposition 88 thereof. The operating element 6 which by way of thelatching part 15 is likewise biased to the distal position 90 thereof,bears on the latching part 15.

In order for the set amount of injection fluid to be squeezed out, theoperator has to move the operating element 6 in the proximal direction31, counter to the force of the spring 23 acting in the direction of thelongitudinal central axis 50. As is shown in FIG. 4, the operatingelement 6 has a stop element 32 which in the position shown in FIG. 4bears on a first stop 33 of the injection sleeve 17. The stop element 32here bears on the proximal side of the first stop 33, being urged by thespring 23 against the first stop 33. As is also shown in FIG. 4, theinjection sleeve 17 has a second stop 34 which is disposed on theproximal side of the stop element 32, in the position shown in FIG. 4being disposed at a spacing from the stop element 32. As is also shownin FIG. 4, the injection sleeve 17 in the injection position 29 shown inFIG. 4 also bears on a stop 25 of the upper housing part 3, whichdelimits the maximum amount of injection fluid to be set.

FIGS. 5 and 6 show the injection device 1 after displacing the operatingelement 6 from the distal position 90 thereof to the proximal position91 thereof, and prior to injection fluid being squeezed out. In theproximal position 91 of the operating element 6, the stop element 32bears on the second stop 34. As is also shown in FIG. 6, the latchingpart 15 has been displaced in the proximal direction 31, to the secondaxial position 89 thereof, by the operating element 6. In this positionthe latching installation 35 is not active such that no latchingpositions can be perceived or heard when injection fluid is beingsqueezed out.

The first coupling 16 is opened in the proximal position 91 of theoperating element. As a result the entrainer 14 can rotate in relationto the operating element 6. As is also shown in FIG. 6, the firstcoupling 16 on the entrainer 14 has latching teeth 38 which in the caseof a closed coupling 16 engage between the latching teeth 53 of theoperating element 6. In the case of an opened coupling 16, the latchingteeth 38 in the direction of the longitudinal central axis 50 aredisposed so as to be spaced apart from the latching teeth 53, beingmutually disengaged. The second coupling 20 in the proximal position 91of the operating element 6 is closed such that the operating element 6is connected in a rotationally fixed manner to the injection sleeve 17and thus also in a rotationally fixed manner to the upper housing part3. If and when the operating element 6 is displaced from the positionshown in FIG. 6 in the proximal direction 31, the injection sleeve 17 byway of the stop element 32 and by way of the second stop 34 moves in theproximal direction. The dosing member 18 is rotated by way of the firstthreaded connection 19. The piston rod 12 is connected in a rotationallyfixed manner to the operating element 6 and, by way of the operatingelement 6, in a rotationally fixed manner to the upper housing part 3.By virtue of the rotation of the dosing member 18, the piston rod 12 ismoved in the proximal direction, on account thereof squeezing out theset amount of injection fluid from the container 5. The entrainer 14 isentrained by the injection sleeve 17 in the proximal direction. Thespring 23 is at least partially relaxed when the operating element 6moves in the proximal direction 31, on account thereof facilitating theinjection procedure.

FIGS. 7 to 10 show the entrainer 14, the latching part 15, and thespring 23. FIG. 8 schematically shows the insertion fit of the two ends84 and 85 of the spring 23 on the latching part 15 and on the entrainer14. The latching part 15 has longitudinal grooves 37 for therotationally fixed connection to the injection sleeve 17. The entrainer14, on the proximal cylindrical portion thereof, has longitudinalgrooves 36 for the rotationally fixed connection to the dosing member18. This cylindrical proximal region at the distal side thereof isdelimited by a periphery 48. As is shown in FIGS. 9 and 10, theentrainer 14 has the inwardly protruding latching teeth 38. The latchingteeth 38 do not extend across the entire internal circumference of theentrainer 14. Four groups of three latching teeth 38 each, which aresymmetrically disposed, are provided in the embodiment. Another numberor arrangement of the latching teeth 38 may also be advantageous. As isalso shown in FIGS. 14 and 15, the entrainer 14 has an opening 47, ineach case on the proximal side of the latching teeth 38. On accountthereof, the proximal end of the latching teeth 38 may be manufacturedin a simple manner in terms of production technology. The latching teeth53 of the operating element 6, which are shown in FIG. 6, in the case ofan opened first coupling 16 are located in the region of the openings47. The spring 23 is configured as a combined compression and torsionspring, biasing the latching part 15 in the distal direction, andbiasing the entrainer 14 in the rotation direction about thelongitudinal central axis 50 in the direction toward the zero position28.

FIGS. 9 and 10 also show the latching installation 35 in detail. Thelatching installation 35 includes a latching element 43 which isconfigured on the latching part 15. A counter-latching element 40 on theentrainer 14 interacts with the latching element 43. Thecounter-latching element 40 is configured on a latching arm 39, beingresilient by virtue of the inherent elasticity of the material. Both thelatching element 43 as well as the counter-latching element 40 in thecircumferential direction are asymmetrically configured. Thecounter-latching element 40 has a latching flank 45, the latchingelement 43 in the latching position coming to lie therebehind. Thefurther flank of the counter-latching element 40 is configured as aguide flank 46 which has a comparatively flat profile. Accordingly, thecounter-latching element 40 is also asymmetrically configured, having alatching flank 45 and a guide flank 46. When setting an amount ofinjection fluid to be squeezed out, the entrainer 14 conjointly with theoperating element 6 is rotated in a first rotation direction. The guideflanks 46 come into mutual contact during this rotation. The guide flank46 of the latching element 43 deflects the counter-latching element 40in a radially inward manner such that the latching positions can bereadily reached. During rotation of the operating element 6 in a secondrotation direction, counter to the first rotation direction, the steeplatching flanks 45 come into mutual contact. The spring 23 isadvantageously conceived such that the force of the spring 23 does notsuffice for the latching flanks 45 to be overcome, so that the injectiondevice 1 is always reset to the next lowest latching position when theoperating element 6 is released between two latching positions. However,a symmetrical layout of the latching elements 40 and/or 43 may also beadvantageous. The latching flanks may be conceived such that theoperator may overcome a latching position that has already been reached,being able to reset the operating element 6 to a lower set dosage. Thelatching flanks may also be conceived such that the latter isimpossible.

FIG. 11 shows an opening 94 on the entrainer 14, the second end 85 ofthe spring 23 (FIG. 8) being hooked into the opening 94. FIGS. 12 and 13show the configuration of the latching arm 39 which carries thecounter-latching element 40. As is also shown in FIG. 13, the periphery48 delimits the circumferential groove 63, the retaining periphery 64 ofthe injection sleeve 17 (FIG. 2) protruding thereinto.

FIGS. 16 to 19 show the latching part 15. As is shown in particular inFIG. 19, the latching part 15 for the rotationally fixed connection tothe injection sleeve 17 has on the external circumference twolongitudinal grooves 37, disposed so as to be mutually opposite. Fourlatching elements 41, 42, 43, and 44, which are of identicalconfiguration and are disposed at dissimilar mutual spacings on thecircumference, are configured on the latching part 15 in the embodiment.The latching element 41 corresponds to the zero position, the latchingelement 42 is assigned to the priming position, the latching element 43is assigned to a first dosage, and the latching element 44 is assignedto a second dosage. The latching part 15 at the distal end side 49thereof is configured in a rounded manner. The latching part 15, by wayof this end side 49, bears on the operating element 6. Low frictionforces result by way of the rounded configuration when the operatingelement 6 is being rotated in relation to the latching part 15.

FIGS. 20 to 24 show the operating element 6. As is shown in FIGS. 20 and21, the entrainment portion 51 of the operating element 6, by way ofwhich the operating element 6 is connected in a rotationally fixedmanner to the piston rod 12 (FIG. 1), is configured by two arms 52 whichextend in the longitudinal direction of the injection device 1. As isshown in FIG. 23, the operating element 6, in the distal region of thecircumferential wall thereof, carries an internal toothing 54 whichinteracts with a toothing 55, shown in FIG. 25, on the externalcircumference of the injection sleeve 17, forming with the latter thesecond coupling 20. As is shown in FIG. 24, the latching teeth 53 whichtogether with the latching teeth 38 of the entrainer 14 form the firstcoupling 16, are likewise not distributed across the entirecircumference of the operating element 6, but are in each case onlydisposed in part-regions. The latching teeth 53 and the latching teeth38 are to be disposed such that it is ensured in every rotationalposition of the operating element 6 in relation to the entrainer 14 thatat least one latching tooth 50 engages with at least one latching tooth38. As is shown in FIGS. 23 and 24, the stop element 32 is configured asan inwardly protruding periphery. No continuous periphery is provided inthe embodiment; rather, four individual and mutually separatedperipheral portions which form stop elements 32 are provided. Duringassembly of the operating element the stop elements 32 snap-fit behindthe first stop 33 of the injection sleeve 17. However, a continuous stopelement 32 which extends across the entire circumference may also beadvantageous.

The injection sleeve 17 is shown in FIGS. 25 to 32. The injection sleeve17 is configured in the shape of a sleeve, having a distal portion 59and a proximal portion 60 which are mutually separated by a groove 56.The stops 33 and 34 are configured on those sides that delimit thegroove 56. The stop elements 32 of the operating element 6 protrude intothe groove 56. The injection sleeve 17 on the internal side thereof hastwo longitudinal webs 58, shown in FIG. 26, which serve for therotationally fixed connection to the latching part 15 and which protrudeinto the longitudinal grooves 37 of the latching part 15. The opening 26through which the outside of the dosing member 18 is visible to theoperator is also shown in FIGS. 25 and 26. As is shown in FIGS. 28 and30 to 32, the proximal portion 60 of the injection sleeve 17, on thatside that is opposite the opening 26, has a longitudinal web 61 which isconfigured as an elevation on the external circumference. Thelongitudinal web 61 has a rectangular depression 62. The configurationof the depression 62 is shown in detail in FIG. 31.

The depression 62 has a distal edge 86 which in the zero position 28 ofthe injection device 1 interacts with a distal edge 78, shown in FIG.42, on the upper housing part 3, forming with the distal edge 78 thefirst stop 24. The depression 62 has a proximal edge 87 which in theinjection position 29, shown in FIG. 4, which corresponds to the maximumsettable amount of injection fluid to be squeezed out, bears on aproximal edge 79 of the upper housing part 3 (FIG. 42), forming with theproximal edge 79 the second stop 25. The second stop 25 delimits themaximum settable amount of injection fluid to be squeezed out.

As is shown in FIGS. 42 and 43, the upper housing part 3 has adepression 76 which is configured as an approximately rectangularlongitudinal groove, a longitudinal web 77 rising therefrom. Thelongitudinal web 61 of the injection sleeve 17 protrudes into thedepression 76. On account thereof, the injection sleeve 17 in thecircumferential direction is secured against rotating in relation to thehousing 2. The longitudinal web 77 of the upper housing part 3 protrudesinto the depression 62 of the injection sleeve 17, forming with thedepression the stops 24 and 25. The longitudinal web 77 and thedepression 62 also form an anti-rotation security feature for theinjection sleeve 17. As is shown in particular in FIG. 30, the injectionsleeve 17 in the proximal portion 60 thereof carries an internal thread57.

The dosing member 18 is shown in detail in FIGS. 33 to 36. The dosingmember 18 on the external side thereof carries an external thread 65which with the internal thread 57 of the injection sleeve 17 (FIG. 30)forms the first threaded connection 19. The dosing member 18, in theregion of the external thread 65, has the graduation 66, shown in FIGS.33 and 34, which indicates to the operator the set amount of injectionfluid. As is shown in FIGS. 33 to 35, the dosing member 18 on theproximal side thereof has latching hooks 67. As is shown in FIG. 42, theupper housing part 3 has an encircling latching periphery 75, thelatching hooks 67 hooking thereinto and thus forming the latchingconnection 71. As is shown in FIGS. 34 and 35, the dosing member 18 onthe proximal side thereof has a mounting pin 70 which is mounted in abearing sleeve 74 of the upper housing part 3 (FIG. 42). On accountthereof, the dosing member 18 is rotatably mounted in the upper housingpart 3. As is shown in FIG. 35, an internal thread 68 is disposed in themounting pin 70. The internal thread 68 interacts with the externalthread 92 of the piston rod 12, shown in FIGS. 37 and 38, and with thelatter forms the second threaded connection 22. As is shown in FIG. 36,the substantially sleeve-shaped dosing member 18, on the internalcircumference thereof, has a total of four longitudinal webs 69 whichserve for the rotationally fixed connection to the entrainer 14. To thisend, the longitudinal webs 69 protrude into the longitudinal grooves 36of the entrainer 14, which are shown in FIGS. 11 to 13.

As is shown in FIGS. 37 to 39, the piston rod 12 on the distal sidethereof has a guide portion 72 which has a rectangular cross sectionwhich in the embodiment is square. The arms 52 of the operating element6, which are schematically indicated in FIG. 39, bear on oppositelongitudinal sides of the guide portion 72, on account thereof producinga rotationally fixed connection between the operating element 6 and thepiston rod 12. The piston rod 12, on the proximal region thereof, has agroove 73 to which the piston disk 13 is hooked (FIG. 2).

As is shown in FIG. 42, the upper housing part 3, in the proximal regionthereof, has latching hooks 80 which serve for the latching connectionto the holder 4 which is shown in FIGS. 44 and 45. The holder 4 in thedistal region thereof has latching openings 81 into which the latchinghooks 80 hook. Two latching hooks 80 and two latching openings 81 areshown in the embodiment. The latching installation 9 is also shown inFIGS. 44 and 45. The latching installation 9 is formed by two mutuallyopposite latching hooks 82 which latch onto the container 5. The holder4, on the external circumference thereof, in the proximal region has anexternal thread 83 onto which the injection needle 8 (FIG. 1) isscrewed.

In the embodiment as per FIGS. 1 to 45 the spring 23 fulfills a dualfunction, since the former has to both generate torque between theentrainer 14 and the latching part 15 as well as bias the latching part15 and the operating element 6 in the distal direction. In order for thelayout of the spring 23 to be simplified, separate spring elements maybe provided for generating the axial force and for generating thetorque. A respective embodiment is shown in FIGS. 46 to 52. The samereference signs are used for designating corresponding elements in allfigures of the present application. An injection sleeve 97 in which alatching part 95 and an entrainer 14 are disposed is shown in FIGS. 46and 47. The injection sleeve 97 has an inwardly protruding supportperiphery 98 on which a first end 84 of a spring 93 is secured. A secondend 85 of the spring 93 is hooked to the entrainer 14. The spring 93serves for generating torque between the injection sleeve 97 and theentrainer 14. Since the entrainer 14 is connected in a rotationallyfixed manner to the dosing member 18, the torque acts between the dosingmember 18 and the injection sleeve 97, biasing the dosing member 18 inthe direction toward the zero position 28 of the assembly.

As is shown in FIGS. 48 to 52, the latching part 95, on the proximalside thereof, has two spring arms 96. In the embodiment the spring arms96 are configured preferably from plastics so as to be integral with thelatching part 95. By virtue of the inherent elasticity thereof, thespring arms 96 bias the latching part 95 in the distal direction.Instead of the spring arms 96, a screw compression spring or a springelement of another configuration may also be expedient for biasing thelatching part 95 and the operating element 6 in the direction of thelongitudinal central axis 50.

A further embodiment of an injection device is shown in FIGS. 53 to 58,wherein only the injection sleeve 107 and the entrainer 114 are shown.The further elements which are not shown correspond to the componentswhich are shown and described in the context of the injection device 1.As is shown in FIG. 54, the injection sleeve 107, on the internalcircumference thereof, has latching elements 101, 102, 103, and 104. Thelatching elements 101, 102, 103, and 104 establish the latchingpositions of the injection device 1. As is shown in FIG. 54, thelatching elements 101 to 104 on the circumference have dissimilar mutualspacings. The latching element 101 is assigned to the zero position, thelatching element 102 is assigned to the priming position, and thelatching elements 103 and 104 are assigned to a first and second amountof injection fluid to be squeezed out.

As is shown in FIGS. 56 to 58, the entrainer 114 has a latching arm 109on which a counter-latching element 110 is configured which, fordefining the latching positions, may interact with the latching elements101 to 104. Since the relative position of the injection sleeve 107 andof the entrainer 114 by virtue of the retaining peripheries 64 whichprotrude into the circumferential groove 63 is predefined, the latchinginstallation which is formed by the latching elements 101 to 104 and thecounter-latching element 110 is effective both when setting an amount ofinjection fluid to be squeezed out and when squeezing out the injectionfluid from the container. As is shown in FIGS. 55 and 58, the latchingelements 101 to 104 and the counter-latching element 110 in thecircumferential direction are configured so as to be approximatelysymmetrical such that no excessive force is required in order toovercome the latching positions when the injection fluid is beingsqueezed out. In the case of the injection device which is shown inFIGS. 53 to 58, no spring is provided which biases the dosing member inthe direction of the zero position. A step 108 for bearing a compressionspring which acts between the injection sleeve 107 and an operatingelement (not shown in FIGS. 53 to 58) and which biases the operatingelement in the distal direction is provided on the internalcircumference of the injection sleeve 107.

A further embodiment of an injection device 121 is shown in FIGS. 59 to62. The injection device 121 has an upper housing part 123, a latchingarm 129 being configured thereon. The latching arm 129 in the embodimentis visible from the outside. However, the latching arm 129 isadvantageously configured such that the former is invisible to theoperator. The injection device 121 has an injection sleeve 127 whichsubstantially corresponds to the injection sleeve 17 of the injectiondevice 1. However, the injection sleeve 127, on the external sidethereof, has latching elements 128 which are configured as depressionsand into which a counter-latching element 130 which is configured on thelatching arm 129 and which in the embodiment is configured as a latchcan latch, so as to form with the latching elements 128 a latchinginstallation 125. As is shown in FIG. 61, the injection device 121 hasan entrainer 124 which does not carry any latching elements orcounter-latching elements. A latching part is also not provided. Aspring 133 which biases the operating element 6 in the distal directionis disposed in the operating element 6. In the embodiment, the latchinginstallation 125 acts between the upper housing part 123 and theinjection sleeve 127 both when setting an amount of injection fluid tobe squeezed out, as well as when the injection fluid is being squeezedout of the container 5. However, it may also be provided that thelatching arm 129, when the operating element 6 is being readjusted tothe proximal position 91 thereof (FIG. 6), is deflected such that thecounter-latching element 130 cannot interact with the latching elements128. This is expedient in particular when the latching arm 129 isdisposed not on the upper housing part 123 but on the injection sleeve127, the latching elements 128 being disposed on the upper housing part123.

In the case of the injection device 121 shown in FIGS. 59 to 62, aspring which biases the dosing member in the second rotation directionand which acts between the injection sleeve 127 and the dosing membermay also be provided. As is shown in FIG. 62, the latching element 128and the counter-latching element 130 in the embodiment shown aresymmetrically embodied. If and when a spring is additionally providedfor biasing the dosing member in the second rotation direction, it maybe expedient for the latching elements to be asymmetrically configuredsuch that dissimilar forces for overcoming the latching positions whensetting and when squeezing out the injection fluid result, theadditional spring in each case being able to turn back the dosing memberonly to the next lowest envisaged amount of injection fluid.

A further embodiment of an injection device 131 (FIGS. 70 and 72) isshown in FIGS. 63 to 73. The dosing member 138 of the injection device131 is shown in FIGS. 63 to 66. The dosing member 138 on the distal sidethereof has a latching arm 139 which carries a counter-latching element140. The further construction of the dosing member 138 correspondssubstantially to the construction of the dosing member 18. As is shownin FIG. 66, the counter-latching element 140 in the embodiment issymmetrically configured. As is shown in FIGS. 67 to 69, the injectiondevice 131 has an injection sleeve 137 which, on the internalcircumference thereof, carries latching elements 141 and 142. Thelatching elements 141 and 142 in the embodiment are configured asdepressions. Further latching elements may be provided. It may beadvantageous for the latching arm 139 to be configured on the injectionsleeve 137 instead of on the dosing member 138, and for correspondinglatching elements or latching depressions to be provided on the dosingmember 138. The latching elements 141 and 142 are mutually offset bothin the direction of the longitudinal central axis 50 as well as in thecircumferential direction. The latching elements 141 and 142 lie on ahelical path which corresponds to the thread pitch of the externalthread 65 of the dosing member 138. On account of the latching elements141 and 142 being mutually offset both in the direction of thelongitudinal central axis 50 as well as in the circumferentialdirection, comparatively minor spacings between the latching positionsare possible.

The injection device 131 is shown in the zero position in FIGS. 70 and71. The latching element 141 is latched to the counter-latching element140, forming with the latter a latching installation 135. The injectiondevice 131 in FIGS. 72 and 73 is located in an injection position. Thecounter-latching element 140 is latched to the latching element 142. Byvirtue of the symmetrical configuration of the latching elements 141,142, and of the counter-latching element 140, the latching positions inboth rotation directions may readily be bridged by the operator, so thatthe operator may reset the injection device 131 from an already setdosage to the zero position, without injection fluid being squeezed out.However, another asymmetrical layout of the latching elements may alsobe expedient. A spring which biases the dosing member 138 in the secondrotation direction may also be provided between the injection sleeve 137and the dosing member 138 in the case of the embodiments of an injectiondevice 131 shown in FIGS. 63 to 73. Since the injection sleeve 137 inrelation to the dosing member 138 moves not only in the circumferentialdirection but also in the axial direction, a set amount of injectionfluid is unequivocally assigned to each relative position of theinjection sleeve 137 and of the dosing member 138, even in the case of aplurality of revolutions of the operating element 6 up to the maximumdosage.

It is understood that the foregoing description is that of the preferredembodiments of the invention and that various changes and modificationsmay be made thereto without departing from the spirit and scope of theinvention as defined in the appended claims.

What is claimed is:
 1. An injection device defining a longitudinalcenter axis, a proximal direction and a distal direction, the injectiondevice comprising: a housing; a dosing member held so as to be rotatableand fixed in said housing in the direction of the longitudinal centeraxis; an injection sleeve held so as to be rotationally fixed inrelation to said housing and displaceable in the direction of saidlongitudinal center axis; said dosing member being connected to saidinjection sleeve via a first threaded connection; said dosing memberbeing configured to rotate in a first rotational direction in relationto said housing when an amount of injection fluid to be dispensed isbeing set; said injection sleeve being configured to move in the distaldirection because of said first threaded connection; said dosing memberbeing further configured to rotate in a second rotational directioncounter to said first rotational direction when said amount of injectionfluid to be dispensed is being pressed out; said injection sleeve beingconfigured to move in the proximal direction because of said firstthreaded connection; a container configured to contain injection fluid;a dosing piston configured to press injection fluid out of saidcontainer; said dosing piston being connected to said dosing member viaa second threaded connection; said dosing piston being connected to saiddosing member in a rotationally fixed manner so as to rotate conjointlytherewith when said amount of injection fluid to be dispensed is beingset; said dosing piston being connected to said injection sleeve in arotationally fixed manner when said amount of injection fluid to bedispensed is pressed out and, by virtue of said second threadedconnection, is moved in the proximal direction; a latching unitconfigured to act at least when said amount of injection fluid to bedispensed from said container is being set, where said latching unit hasa latching element and a counter-latching element configured to interactwith the latching element in a latching position; and, said latchingunit being configured to act between the injection sleeve and dosingmember which, during setting of the amount of injection fluid to bedispensed, move relative to one another, wherein a set amount ofinjection fluid is unequivocally assigned to each relative mutualposition of the injection sleeve and the dosing member, wherein alatching part is connected with one of the dosing member and theinjection sleeve in a rotatably fixed manner and such that the latchingpart is displaceable relative to the one of the dosing member and theinjection sleeve, and wherein the latching element being arranged on thelatching part.
 2. The injection device of claim 1 further comprising: afirst coupling; an entrainer connected to said dosing member in arotationally fixed manner; a second coupling; an operating elementconfigured to be connectable to said entrainer in a rotationally fixedmanner via said first coupling and to be connectable to said injectionsleeve via said second coupling; said operating element having a distalposition and a proximal position in relation to said injection sleeve;said operating element being configured to be connected to saidentrainer in a rotationally fixed manner via said first coupling whensaid operating element is in said distal position; said second couplingbeing open when said operating element is in said distal position so asto enable said operating element to rotate in relation to said injectionsleeve; said first coupling being configured to be open when saidoperating element is in said proximal position; said operating elementbeing configured to be rotatable in relation to said entrainer and to beconnected to said injection sleeve in a rotationally fixed manner viasaid second coupling when said operating element is in said proximalposition.
 3. The injection device of claim 2, wherein said latching unitis active when said operating element is in said distal position.
 4. Theinjection device of claim 2, wherein said entrainer is, in the directionof the longitudinal center axis, coupled to a position of said injectionsleeve.
 5. The injection device of claim 1, wherein said latching partis biased in the direction of said first axial position.
 6. Theinjection device of claim 5, wherein said latching part includes atleast one spring arm configured to bias said latching part in thedirection of said first axial position.
 7. The injection device of claim1 further comprising a spring configured to act between said injectionsleeve and said dosing member and to bias said dosing member in saidsecond rotational direction.
 8. The injection device of claim 7 whereinsaid spring has a first end fixed on said injection sleeve and a secondend fixed on said entrainer.
 9. The injection device of claim 2, whereinsaid latching part is in the second axial position when the operatingelement is in the proximal position.
 10. The injection device of claim1, wherein the latching element is configured to be able to engage thecounter-latching element in a first axial position of the latching partand to be disengaged from the counter-latching element in a second axialposition of the latching part independent of the relative mutualposition of the entrainer and the injection sleeve.